2004BaltA..13..177M

Gamma-ray bursts (GRBs) are sudden and intense flashes of gamma-rays, which appear to be the most energetic explosions in the Universe. Major advances have been made in the last several years, including the discovery of slowly fading X-ray, optical and radio afterglows of GRBs, the identification of host galaxies at cosmological distances and finding evidence for many of them being associated with star forming regions and supernovae. Progress has been made in understanding how the GRB and afterglow radiation arise. These advances have opened new vistas and questions on the nature of the central engine, the identity of their progenitors and the effects of the environment.